Watch the Trailer for 'Pretty Little Liars: The Perfectionists' Before Someone Snaps

PLL alumni Sasha Pieterse and Janel Parrish return as Alison DiLaurentis and Mona Vanderwaal, respectively. They will be joined by Sofia Carson as Ava, Sydney Park as Caitlin, Eli Brown as Dylan, Graeme Thomas King as Jeremy, Kelly Rutherford as Claire, and Hayley Erin as ... we don't know yet.

Here's what we do know: "Someone is about to snap. And kill."

That's per the first trailer, which just took us to the town of Beacon Heights, "a seemingly perfect town" where "a group of three college friends struggle with the stress of being overachievers. In the aftermath of the town's first murder, each Perfectionist hides behind a secret, a lie and an alibi."

Check out the trailer:"The Perfectionists," like "Pretty Little Liars," is adapted from author Sara Shepard's books. PLL aired for seven seasons, ending last year on Freeform. This will be the second PLL spinoff after "Ravenswood," which only lasted one season.